Plastic chains are widely used for the transport of bottles and cans at high speeds. It is also common to have chains running in parallel at different speeds and to transfer the goods (i.e., bottles, cans or the like) from one chain to the parallel running adjacent chain. Some of these chains are designed to be able to move straight as well as to negotiate a curve. The different speeds of the respective chains causes the goods to be accelerated or decelerated when the goods change from one chain to the next. During the changeover, the goods are shifting not only transversely, but also longitudinally over the chain surface. In order to prevent the goods, particularly bottles and the like, from tilting over, it is important for the chains to provide a smooth surface. This requirement becomes particularly important if a chain suitable for negotiating curves is used. An example of a chain for use with a curved track is shown in U.S. Pat. No. RE 38,543. The chain disclosed in this patent has convex front edges matching with the concave rear edge of the adjacent link module. The two mating edges need to have a small gap. When the chain is negotiating a curve, the gap becomes larger at the portion of the chain located on the outside of the curve. This is an important area for moving bottles or the like over these gaps without tilting.
There have been chains provided with finger-like overlapping of link plates as, for example, shown in U.S. Pat. Nos. 5,697,492 and 6,347,699. These chains however have the disadvantage of lengthening the gap line drastically and therefore increasing the unevenness of the surface for transversal movement over the chain surface.
Accordingly, there is a need for an improved chain module design that provides a smoother surface to reduce the risk of tilting bottles.